The Study On Water And Land Use Evolution In South Lake Of Wuhan Based On RS And GIS

Wetlands and forests, oceans, and as the world's three major ecosystems, They have played huge roles in flood and drought prevention, control soil erosion, regulating climate, biodiversity conservation and tourism.The lakes of city play an importantrole of the ecosystem. Recent years, as unreasonable development and use of lakes of city, wetland ecosystem is deteriorating, and its functions are under serious threat. Now they are facing serious ecological and environmental pressures.So, protecting and restoring the city resources and rebuilding a healthy wetland ecosystem in the wetlands of city are major strategic sustainable urban development issues.In this study of South Lake in Wuhan, using ERDAS image processing system and the ArcGIS platform for the study, analysis and interpret four remote sensing images in 1989, 1995, 2000 and 2005. We get the evolution trend of wetland water, land use change of south Lake in 1989-2005, based of which we get the driving force of evolution.The main conclusions are as follows:(1) Analysis waters evolution of South Lake in the past 16 years. We can find that there are big variations in the area of South Lake. The area was 1539 hm2 in 1989 but only left 789 hm2 in 2005 which decreased 750 hm2. The water area became small quickly.(2) From the fractal dimension of the whole South Lake shoreline, we can see that the fractal dimension of South Lake shoreline continued to get lower from 1989 to 2005. The fractal dimension of South Lake shoreline decreased slowly from 1989 to 2000, because of less human disturbance while dimensional changes are significant from 2000 to 2002 due to the strong human disturbance.(3) From the view of the whole range of land use change of South Lake area, we can figure that variations of construction land, water and arable land changed a lot. The proportion of area of the types of land use in 1989 is as follows:construction land> water>grassland>farmland>woodland>unused. In 2005 the proportion of various land use area change into the order as follows:construction land>water>grassland> woodland>unused>farmland. That is to say. The proportion of different land use type of the study area in 1989 is different from that in 2005.(4) From the view of the changing speed of land use in South Lake area from, construction land, water and arable land changes fast while woodland, grassland and land use changes slowly.(5) South Lake area from the diversities of land use type conversion in different periods, the transfer matrix conversion of the three periods was obvious. The conversion area in 2000 to2005 is larger than the first two phases, indicating that changes in land use in 2000-2005 are obvious. The water area within the region gradually converted into construction land, and cultivated area also mainly changes into construction land. The increasing of the construction area during the economic expansion process make the water and arable land area decrease sharply in South Lake area.(6) From the characteristics of the overall transformationof land use type in South Lake area, during the study period, the order of land use dynamic change in the South Lake area are:water into construction land>grassland converted into construction land> Land Conversion construction land>forest land into construction land>water into the grass>unused land into construction land>construction land into forest land> construction land into grassland>arable land into grassland>woodland into grassland> into construction land is not use to>unused land into cultivated land>grassland into unused land>grassland into forest land>water into land>land into forest land>water into unused land>of unused land into grassland>woodland into waters>unused land into forest land>water into the woodland>arable land into construction land>land into the water>grassland conversion to cropland>woodland into grassland into arable land waters. Construction sites, water and arable land are the most important transformation.(7)After analysis we can obtain that population, urbanization and industrialization are the main reasons for wetland changes in the South Lake area.